Worse, the sources of infection are unclear, the steering board said in an update.
The 420th case was a woman in Da Nang who visited her daughter in an apartment condo in Lac Long Quan in District 11 from June 21 to July 8.
Presently, she is living with her husband, son and daughter-in-law in a house in Hoang Dieu Street in Hai Chau District. A few days before she had fever, she and her husband come to a local wholesale market to buy something. When she was suffering fever and pain in chest, she visited her younger brother at a house in 2/9 Street in Hai Chau District.
Her husband on July 16 went to a local drug stores to buy medicines for her; but after five days of taking medicines, her condition has not abated; therefore, she was taken to the Da Nang C Hospital on July 21 and then returned home. She received three relatives hailing from the Central Province of Quang Nam at home.
Because of unpredictable development of infection cases, 50 soldiers of the Military Zone 5 Command yesterday sprayed disinfectants in the Da Nang C Hospital and the Da Nang General Hospital. The two infirmaries have isolated all medical workers, relatives of patients and those who take care of patients.
The General Hospital in Quang Ngai Province where the 419th infection case is being treated announced to stop admitting patients from July 27 for Covid-19 prevention.
The Da Nang authority has banned crowded events as well as closed non-essential services to stall the virus. Authorities are conducting aggressive contact tracing to prevent the virus from spreading further.
Vietnam has reported 420 Covid-19 cases so far.